Process of treating metallic ores.



A. STELLE.

PROCESS 0F TREATING METALLIC ORES.

APPLICATION FILED APR. 6. 1914.

1,162,150. Patented 11017.30, 1915.

2 SHEETS-SHEET l.

a 'M A, @am I A. ESTELLE.

PROCESS 0F TREATING METALLIC ORES.-

APPLlcATloN FILED APR. 6. |914.

1,1 62,1 v50. Patented Nov. 3o, 1915.

2 SHEETS-SHEET 2.

and Ferrous .rohzljoj/ ,Solale annales.

W1' fl? 53 9,5' l v In V022 for 2, c. Capm AXEL ESTELLE, OF HAGEN, WESTPHALIA, GERMANY.

PROCESS 0F TREATING METALLIC DRES.

Specification of Letters Patent.

Patented Novo, reis,

Application filed April 6, 19l4. Serial No. 829,945.

To all whom t may conce/rn.'

Be it known that I, Axnr, ject oli the King of Sweden, residilw at Hagen, l/Vestphalia, Prussia, Germany, ave invented certain new and useful'lmprovements in Processes of Treating Metallic Ores, of which the following is a specification.

My invention relatesto a process of eliminating useful constituents from ores and smeltmg products, containing essentially the sulfur compounds of iron, and particularly to a process of elil'ninating the iron.

'lhel sulfids of iron which exist in abundant quantities in nature, as iron pyrites and magnetic pyrites, as well as the whole ofthe orcs which consist mainly of the sulfur compounds of ironyare, as is well known, scarcely ever regarded strictly as iron ores because owing to the 'sulfur contained in them they can only in rare cases be employed as raw Vmaterial for the production of iron. These ores, especially iron pyrites,

have consequently heretofore been mainly employed in the chemical industry for the manufacture of sulfurous and sulfuric acids,` and are only ofimportance for metallurgical purposes when they contain4 a suliicently large percentage of metals of some value, such as gold, silver, copper, nickel, cobalt andrso on. The main constituents, iron and sulfur, are regarded only as encumbering admixtures .which must be removed in the form of slag Ior be Kburnt olii'.

The subject-matter of the present invention is a process, which enables said ores to be turned to better account than heretofore, so that not only'are extraneous metals which may be contained therein almost completely eliminated in a highly concentrated form, but also both the iron and the sulfur are eX- tracted, the former largely or entirely as a very pure electrolytic ironand the latter ,in a pure and uncontaminated form. p y The process according to this invention consists essentially in first leaching the raW vmaterial with yweak non-oxidizing acid and in then precipitating the iron electrolyti'- cally with insoluble electrodes from the solution of the salt of iron so formed, a suitable method being employed for continu-` ously regenerating the solution'.

The various steps of the lprocess are dia, grammatically vrepresented in the two sheets of drawings fledherewith.

lils'rnLLn, a sub-l Figure 1 illustrates the various steps by which the iron and sulfur are separated from each other and from the residue of the ore, the leaching being done simply by, a

' dilute non-oxidizing acid. Fig. 2 illustrates the same when a part oi the ferrie solution produced by electrolysis is used with such dilute non-oxidizing acid as leaching fluid. The process is the same step for step, the difference being the addition of supplemental leaching liquid at one stage to the main leaching liquid first above mentioned. Of course the materials produced, evolved or separated by the various steps of the process may be collected, washed and used where available in continuation or repetition vof the process as applied to first ore.

In carrying out this process, it is requisite `that the raw material to be treated can be actually and sufficiently lixiviated by the dilute acid. This is readily attainable in the case of the monosulfid of iron, z'. e. ferrous sullidr FeS, but the disuld of iron, or ferrie sulfid, FeS2, is .practically insoluble in the same acids. In the sulfur compounds of iron existent in nature, however, the ratio of sulfur tol iron is in every case higher than in ferrous'sulfid and these compounds are consequently more' or less difficult to dissolve. When treating this raw material, the excess quantity of sulfur must first of all be removed and the suld of iron be thus brought into a readily soluble form. When the proportion ofsulfur is high, as in the case of ironpyrites, the excess sulfur is preferably expelled by the application of intense heat without access of air` for example, in an electric furnace, this sulfur being of practical value as sublimed sulfur, and the gangue'being in certain cases simultaneously removed as slag by employing suitable admixturesi When, on the other hand, magnetic pyrite wherein vthe access sulfur amounts to only 9 to 14%, is employed as raw material, it is preferable to produce or to employ a kind of pyritic smelting, so that, by sacrificing a portion of the iron and sulfur, the gangue may be slagged, and a higherpercentage quantity of any extraneous metals present in the ore may be obtained. Another method I may employ is to cause the excess quantity of sulfur to combine or be chemically saturated with iron or another metal. After the sulfid of iron has been converted into-the nec-` so X essary, readily soluble form, the above def scribed ylixiviation and electrolytic treatment can be carried out.

It has already been frequently proposed to treat copper and zinc ores or. their smelting-products in a similar manner. The known processes involving this treatment are however totally unsuitable, for the present purpose, because, when extracting iron, quite other conditions exist which render necessary a treatment essentially different from these processes.

For carrying the new' process into practice, two cases must be considered l) When the raw material 4contains valuable extraneous metals which it is desired to extractf This case is to be regarded as the normal one. (2) When the raw material contains no such metals.`

The' following is an example of the manner in which the present invention may be carried int ei'ect. The rawmaterial, disintegrated or reduced to a suitable grade, is treatedat a temperature of about 40 to 80 C. with a dilute, non-oxidizing acid, preferably hydrochloric acid. Assuming that the latter acid be employed, the result of the reaction is the formation of ferrous chlorid and sulfureted hydrogen, in accordance with the well known equation:

res+2no1=rec12+n2s (1);

Other sulfur containing metals possibly present, as well asa small residue of gangue, remain behind in the lixiviating apparatus. These particular metals, being in this highly concentrated form, can subsequently be very advantageously realized. The solution ofv ferrous -solution is electrolyzed in suitable deeomposition or electrolytic cells with 1nsoluble anodes, these cells being however of vextremely simple construction because the solution contains only one single metal. A

I portionl of the iron is now deposited while twice this amount or iron is converted into the corresponding ferrie compound, as the following equation shows:

3Fec12=re+2rec13 (2) vareoisuizs:arcoienoH-s (s) The acid previously combined with the electrolytically deposited iron is in this manner again' liberated in order to be available for further use, while the' corresponding, simultaneously separated quantity of sulfur v needs only to be removed and converted by known methods into one of the commercial forms.

By this process there are therefore ex tracted in a simple manner not only the electrolytically depositedr iron but also the ycorrespondingquantity of sulfur. The valuable metals remain behind as compounds with sulfur and can be realized by a separate process. The acidy employed as solvent 1s continually regenerated, and then remployed. ff

A special advantage of this process is that the sulfur is eliminated in `a separate apparatus and is not rendered impure by the residues when the raw material is dissolved. An` added advantage is that the electrolyzing devices can bc of extremely simple construction, as it is a question of keeping several different metals 'separate from one another.

In the above stated second case, viz. when the sulid of iron contains no valuable extra-neous metals or atleast not suliicient quantities of the same to warrant realization, the `above described vprocess may obviously be also employed. Under some circumstances it is however preferable somewhat to modify the process, for, since no valuable extraneous metals need to be taken into consideration, it would be possible directly to lixiviate the sulfid of iron with the ferrie solution ldirectlyobtained from the electrolytic or decomposition cells. For this purpose however a certain quantity of free acid must be present, and as the solution to be electrolyzed should contain no free or at least no material quantity, the acid must be neulg@ tralized or saturated before the solution is subjected to electrolysis. This again would means a continual increase of the quantityr of solution and-a corresponding loss of'acid and iron. This disadvantage can however 19.5 be obviated by supplyin only, a portion of the ferrie solution direct y to the lixiviatinr apparatus, while the remainder is passedv through the absorption tower provided for case No. l, in order to reach the lixiviating apparatus only at' some later time. In this manner the necessary-quantit of free acid is supplied and as this should vbe neutralized, that quantity of sulfureted hydrogen which is necessary to furnish this acid is produced.

By the process forming the subject-matter of this invention it is therefore made possible to produce electrolytic iron from ores and smelting products which have hitherto 12b been regarded as almost worthless. Moreover, the new process is applicable to any sulfid-contaming smelting product, provided that the percentage of soluble sulid of iron is suiiiciently high. I

this invention is not limited in its apphcation to one distinct product, it is of no consequence that the iron is obtained in a crude form as electrolytic crude iron. The decomposition cells can on that account 130 be of very simple construction. s no freel destructive ygas 1s the latterare well acid is present,`and no evolved at the anodes, preserved. *Y p The separated iron is preferably smelted in an electric furnace, this iron beingif desired simultaneously alloyed with other metals for special purposes. l l The iron may also be obtained in a very pure condition, especially when hydrochloric acid is employed as the solvent, in which case contaminationwith sulfur can be easily avoided. Other elements detrimental to the iron, such as arsenic andphosphorus can, without difliculty, be kept away from the electrolytic iron. As already Jstated, the valuable extraneous metals possibly contained in the ore are dissolved only in exceptional cases andvin minute quantities. If metals which are precipitated by iron, e. g. particularly copper, should occasionally be found in the solution, they can be easily eliminated by this solution being electro,l

lyzed. Of. the remaining extraneous meta-ls, practically only nickel, cobalt and zinc need be considered. The two irst named, if they are electrolytically deposited simultaneously with the iron, can only enhance the value of the latter, while the zinc is again eliminated when the iron is smelted.

What I do claim as my invention and desire to secure by- Letters Patent is'. a 1. A process of eliminating useful constituents from ores and smelting products,

'containing essentially the sulfur compounds of iron, consisting in leaching the raw material with a non-oxidizing acid, in electrolytically deposltlng iron from the ferrous solution obtained, in collecting in the leaching apparatus eventually remaining sulfid compounds of other metals, regenerating the solution and returning the same.

2. A. process of eliminating useful constituents from ores and smeltlng products,

with` a lnon-'oxidizing acid, in -electrolytically containing essentially the sulfur compounds i5 of iron not easily dlssolved or insoluble 1n weak acids, consisting in bringing the sulfid of iron in a well' known manner into al readily soluble form, in leaching the product depositing, iron from the ferrous solution obtained, in collecting in the leaching appa-- ratus eventually remaining suld compounds of other metals, regenerating the solution and returning the same.

3. A process of eliminating useful constituents from ores and smelting products, containing' essentially the sulfur compounds of iron consisting in leaching the material with hydrochloric acid, in electrolytically depositing iron from the ferrous solution obtained, in collecting in the leachingvapparatus eventually remaining `suliid compounds of other metals, regenerating the solution andy returning the same.

4;".Aprocess of eliminating useful constituentSfrOm. ores and smelting products,

containing essentially the sulfur compounds of iron consisting in leaching the material with a non-oxidizing acid, in electrolytically depositing iron from the ferrous solution obtained, insoluble anodes being employed, in collecting in the leaching apparatus eventuall `remaining sulid compounds of other meta s'in washing the sulfuretedhydrogen evnlved at leaching with the ferrie solution resulting from electrolysis, in collecting the sulfur so deposited, in employing the mix ture of ferroussolution and acid, obtained by said washing for the leaching of the raw material and so on. p

ln testimony whereof, I have signed my name to this specification in the ,presence of two subscribinwitnesses.

AX LESTELLE. [1.. s.] e

Witnesses:

HELEN NU'FER, ALBERT NUFER.

e,LA 

